Compliance of average- and intermediate-risk women to semiannual ovarian cancer screening

To report rates of compliance with an ovarian cancer screening protocol using serum CA125 and transvaginal sonography (TVS), performed semiannually on an alternating schedule, among participants at average or intermediate risk for developing ovarian cancer.

Two hundred ninety-two women at average or intermediate risk for developing ovarian cancer were randomly assigned to arms of a controlled clinical trial in which they received ovarian cancer screening consisting of serum CA125 alternating with TVS performed semiannually over 18 months, either alone or in combination with ovarian cancer risk education. A computerized tracking system generated screening appointment reminder letters and monitored adherence to scheduled screening. Participants overdue for scheduled screens received follow-up telephone calls consisting of up to four reminder messages left at 1-week intervals, and one to two interim attempts to reach participants between messages. The compliance rate for each screen was calculated as a ratio of the number of participants successfully completing the screen relative to the number expected to attend. Compliance rate by screen was: screen 1 (CA125) (97.3%), screen 2 (TVS) (82.5%), screen 3 (CA125) (79.0%), and screen 4 (TVS) (64.5%). One hundred seventy-two women completed all four screens and were classified as adherent to the screening protocol. Analysis by screening modality suggests that participants were more compliant to screens involving CA125. Age, educational background, distance from screening center, personal or family history of cancer, perceived risk of ovarian cancer, pre-enrollment ovarian cancer screening behavior, receiving an abnormal screen test result, and participation in ovarian cancer risk education sessions were not associated with adherence to the screening protocol or compliance to any of the screens.

Despite extensive follow-up, compliance of average- and intermediate-risk women to an ovarian cancer screening protocol requiring semiannual screening diminishes rapidly. We propose that a semiannual ovarian cancer screening protocol, particularly one including TVS, may be too intensive for use in this population.